1. Field of the Invention
The present invention generally relates to a composite structural material and the method of making the same and more specifically the invention relates to a low cost, lightweight, high strength, long lasting, crack resistant, monolithically formed composite structural material and the method of making the same in which the composite consists of a core constructed from lightweight, granulated scrap or waste plastic bonded together with a relatively inexpensive cementitious slurry binder. The core is covered on one or more of its surfaces with a high strength outer layer constructed of one or more layers of non-woven fabric material impregnated with a cementitious slurry binder having a different formulation than the core slurry binder to effectively bond with the fibers in the layers of non-woven fabric material to form a three-dimensional reinforcement matrix for the outer layer cementitious slurry. The composite of the core and outer layer are co-formed and cured monolithically with the outer layer cementitious slurry being continuous throughout the fibers of the layers of non-woven fabric and the core cementitious slurry being continuous throughout waste plastic core material. Both slurry binders include cement and water as common materials which is sufficient for them to form and cure monolithically. The lightweight scrap or waste plastic serves as an aggregate for the core. The composite structural material can be molded or formed in various shapes and configurations for various purposes.
2. Description of the Prior Art
Various types of composite structural materials are well known and have been utilized for various purposes in forming a desired structural entity. Composite structural materials are frequently formed into panels which include a lightweight core material surrounded by or partially surrounded by an outer layer of high strength material. The core usually provides lightweight characteristics and insulating properties and the outer layer provides strength, durability, fire resistance and in some instances, appearance characteristics. Various procedures have been developed for forming the core and applying an outer skin, layer or coating of various material to the pre-formed core.
Prior U.S. Pat. No. 4,505,449 issued Mar. 19, 1985 and commonly owned with the present application discloses a base having a lightweight foam core and a coating of cementitious material covering portions of the core. U.S. Pat. No. 4,303,722 discloses a panel constructed by bonding inorganic fiber webs to a pre-formed foam panel utilizing a mixture of thermosetting polymer and gypsum. U.S. Pat. No. 4,559,263 discloses the concept of binding a layer of concrete to a pre-formed board of foamed plastic resin to form a roofing panel. U.S. Pat. No. 4,617,219 discloses a reinforced cement structure utilizing non-woven fabric reinforcing material encapsulated in a cementitious composition. U.S. Pat. No. 4,778,718 discloses a panel having a cementitious matrix reinforced with a three-dimensional fabric distributed uniformly throughout the thickness of the panel. U.S. Pat. No. 4,894,270 discloses a folded structure of polymer fabric reinforced cementitious materials. U.S. Pat. No. 4,963,408 discloses a panel in which a pre-formed core is encapsulated with an outer layer consisting of a polymer and load bearing reinforcing filaments.
The above patents and the prior art cited in those patents and the following U.S. patents are relevant to this invention.
3,745,058 PA0 4,050,659 PA0 4,056,251 PA0 4,305,508 PA0 4,436,274 PA0 4,411,723 PA0 4,572,861 PA0 4,693,924 PA0 4,714,715 PA0 4,752,538 PA0 4,764,238 PA0 4,876,151 PA0 4,904,510 PA0 5,030,502
While the above prior patents disclose various composite structures, they do not disclose the specific arrangement of a core formed of scrap or waste plastic and a relatively inexpensive and simple core cementitious slurry binder together with an outer cover formed of one or more layers of non-woven fabric material and an outer layer cementitious slurry having a different formulation than the core slurry binder to effectively bond with the fibers with the components of the composite being co-formed and monolithically formed and cured.